Got more or less a day off and thought, what can I do that won't be strenuous? Ah, delivery guy came with my new argon bottle and while talking, I mentioned the O/A setup, but the tanks weren't theirs. So they needed returned to the local Praxair (GTS). Called them and yep, bring em in.
Ended up making 2 trips. First for the tanks, next I needed a cutting tip since the one it came with hadn't been drilled, and only had 2 holes in it.
Not much sense complaining about it now... Got the new tip, adapter to use my new regulator, and off I went to give it a shot. I think the last time I used that setup was using Kasenit to carborize and surface harden some parts 15-18 years ago. 
Cut the corner off a piece of 3/8 steel, then heated up a few pieces with a welding tip. Tried the rosebud heating gizmo but not seeing a great reason for that offhand.
Didn't put the new regulators on yet just because I had the old ones on when the new needed adapters I didn't have. Well, one anyway. I'm wondering if they're better suited to welding than the ones I've got. They seem a bit touchy for setting up the small brazing tip.
Looks like it's gonna be fun learning some on that this weekend. Likely, to be used little to none once it's all said and done.
Total cost for the day, $115.
